import java.util.ArrayList;
import java.util.Scanner;
import java.util.Stack;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Test {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextLine()) { // 注意 while 处理多个 case
            String s = in.nextLine();
            Stack<Character> stack = new Stack<>();
            char[] arr = s.toCharArray();
            for(int i = 0;i < arr.length;i++){
                if(!stack.isEmpty() && stack.peek() == arr[i]){
                    stack.pop();
                }else {
                    stack.push(arr[i]);
                }
            }
            if(stack.isEmpty()){
                System.out.println('0');
            }else {
             StringBuilder ret = new StringBuilder();
             for (char c : stack){
                 ret.append(c);
             }
                System.out.println(ret);
            }
        }
    }
}